Pump



Patented Nov. 24,1942

Matthew W. Huber, Chicago, Ill., assigner to Hydraulic Controls, Inc., a corporation of Illinois' Application January 16, 1942, Serial No. 427,085 4 Claims. (ClT 10S- 474) This invention relates to high pressure displacement pumps and particularly to pumps in which the cylinders are vradially arranged.

The invention relates particularly to pumps of the type disclosed inthe application of Harvey S. Pardee, which since the tiling of the present substantial and unit pressures are high. 'Ihe bearing area between slipper and plunger cannot be increased. being coextensive with the end of the plunger.A Use of a simple cylindrical plunger is dictated by the requirements of precise manufacture at reasonable cost. Indeed, many feaapplication has issued as Patent No. 2,271,570,

February 3, 1942', -under which applicant's assignee is operating. In the Pardee pump, an

even number of single acting cylinders (usually four or eight) are used,-and these cylinders are oiiset from true radial lines in a direction opposite to the direction of rotation of the drive shaft. The drive shaft carries an eccentric onwhich a sleeve is rotatably mounted by means of a needle bearing. Between the sleeve and each pump plunger is a crescent shaped slipper which ciers a concave cylindrical bearing contacting the sleeve and a convex cylindrical journal which is received in a concave cylindrical bearing machined across the inner end of the plunger. Flanges at the ends of the Journal on the slipper limit motion of the slippers in the direction of the axis of the sleeve.

A plurality of bow or arcuate wire springs ccnnect opposed plungers in pairs, and flex slightly tures of the design are critical to an extent not obvious at first glance.

Failure of a spring, which vhas proved to be l a rare occurrence, releases two slippers. Convtrary to what might be expected, this does not necessarily wreck the pump, but it does involve serious risk. y

The purpose of the present invention is to attach the slippers to their plungers, without increasing theunit pressure between the slipper and plunger, 'and without weakening the plunger,

and to do so within the very limited clearances imposed by controlling design factors. The attaching' element carries no operating load under normal conditions, but serves to prevent the ,escape of a slipper in the event that a plunger should stick slightly on the suction stroke.` It

as the pumps run, to accommodate slight dif- 'ferences in the instantaneous velocities of the two opposed plungers, such diderences being entailed by the geometry of the crank and connect-- ing rod couples comprising the eccentric and each slipper. y

In the Pardee pump the .slipper is not posialso prevents the escape of the slipper upon spring failure.

The construction here disclosed involves the use of a stirrup which is formed of wire, is

" seated in a groove in the concave bearing of tively connected either to the 'sleeve or to the plunger. 0n the contrary, the assembled relation is maintained by the springs which are mounted under sufiicient initial tension `toensure that the parts will be held in close engagement at all times. This implies suillcient tension to pull the plunger through its suction stroke and maintain under all conditions a thrust engagement with the slipper.

In commercial ps having plunger strokes and cylinder cores each oi the order of inch, this action is consistently secured, as evidenced by oscillograph studies, at speeds up tc at least 3500 R. P. M. though the usual operating speed is 1750 R. P. M. At such speeds the pump has good operating characteristics delivering against discharge pressures from 2500 to 3000 pounds per square inch.

Obviously precise manufacture, the elimination of excess weight in the plungers, and the use of excellent heat treated material are essential to sustained performance because inertia effects are the slipper and enters into hooked engagement in diametrically opposite sockets drilled in the plunger. This slightly reduces the bearing area between the slipper and sleeve, but the enect is not objectionable, as demonstrated by test runs of sufllcient duration to disclose inherent weaknesses had they been present. Retention of the slipper on the plunger reduces the element of risk above set forth, 'and can be ensured by the use oi a wire clip of remarkably small dimensions.

.A preferred embodiment of the invention will now be described by reference tothe accompanying drawing, in which:

Fig. 1 shows a commercialf-eight'cylinder pump with the front cover plate removed to show the invention applied. In the Patent Oillce drawing, Figure lis approximately full size.

Fig. 2 is a fragmentary section on the line 42-2 of Fig. 1, drawn at twice the scale of Fig. 1.

Fig. 3 is a detail view of one plunger and slipper withy the slipper engagingv a portion of the eccentric sleeve, and the retainer stirrup in place.

Fig. 4' is aperspective view showing the stirrup engaged withv the slipper, and the two about to be assembled with a plunger.

Referring first to Fig. l, 8 lrepresents the body nection 1 and a discharge connection 8 and a plurality of radial bosses 9 which house the cylinder bushings II. Eight such bosses are shown in Fig. 1, the pump being 'of the eight cylinder type. The bosses 9 are bored to receive cylinder bushings II which are pressed to place and seat against shoulders I2. The housing 6 is provided with passages I3 which communicate with the inlet passage 1 and with inlet ports I4 which are drilled in the bushings II and which are exposed by the plunger I5l when the plunger I5 moves radially inward to its limit of motion.

The discharge chambers I6 all communicate with the discharge connection 8. Cup-shaped discharge valves I1 of lgenerally cylindrical ccntour are urged inward, that is', in a closing direction by coil compression springs I8, whose inner ends are housed within the cup-shaped valves i1 and whose outer ends are received in sockets in the screw plugs I8, one of which is screwed into each of the bosses 3. Each valve I1 seats against the outer end of the corresponding bushing II and the parts are so dimensioned that at the extreme outer 'limit oi motion of each plunger I5, the plunger engages the valve I1 and holds it off its seat. shown in Fig. 2.

The pump shaft appears at 2! and carries keyed to it an eccentric 22. In the example illustrated, it is understood that the shaft 2I turns counterclockwise, and it will be observed that the axis 'I'his position is of each of the cylinder bushings II isoilset clock-v wise slightly from a line radial to the center of shaft 2|.

The shaft 2| is mounted in bearin'ss of the ball type, one of which appears at 23. These bearings are mounted in the main housing 24 of the pump, only'afragment'of which appears in' Fig. 2. Mounted on the eccentric 22 is the sleeve 25 and interposed between the sleeve and the eccentric are a sexies of bearing rollers 25 which because of their small diameter relatively to their length, form what is commonly known as a needle bearing. The needles are confined by the discs 21 and 28. `Each of the plungers I5 is formed at its inner end with an arcuate seat 23 which is machined across the entire inner end of the plunger and seats on a convex cylindrical iournal 3| which is formed on the slipper, generally indicated by the reference numeral 32.

As a convenient means for limiting the motion of the slipper in a direction transverse to the plunger I5, iianges 33 are provided at the two ends of the slipper. The lower face of the slipper of the pump which is provided with an inlet con- So far, the pump conforms to the Pardee design and no novelty for the pump is here claimed. To establish a retaining connection between each plunger I5 and its slipper 32vthere is provided,

according to the present invention, a transverse groove or slot 38 which is cut across the face of the bearing 34 on slipper 32. The depth of this Vclot slightly exceeds the diameter of the Wire used for the stirrup about to be described.

Seated in this groove is. a stirrup 39 which is of generally U-shaped configuration with its ends inturned as indicated at 4I so as to enter sockets 42 drilled in'opposite sides of the plunger I5. Stirrup 39 is slightly resilient and is so ad- `iusted as to hold the slipper snugly against the end of the bearing 29 in the plunger I5. The passage 43 indicated n Fig. 2 is for oil distribution purposes. y

A characteristic of the stirrup construction is its resilience and the form of the slipperv 32 is such that the groove 3l in the slipper is not strictly concentric with the journal II and cannot be made so. From this it follows that as the slipper turns in the bearing 25, the distance between the groove 38 and the sockets 42 changes slightly. v

In describing the.- invention, an embodiment particularly adapted to a commercial pumpof struction causes the bushing to guide the plungers the Pardee design is described. To some extent. details are dependent on the exact design of the pump and modifications within the general scope of the inventionare possible and are contemplated. Consequently, the embodiment described in considerabledet'ail is intended to be illustrative and not limiting.

I claim:

1. The combination of a pump, comprising at `least one pair of substantially opposed single acting pistons, an eccentric sleeve interposed between said pistons, slippers, one slipper interposed between each piston and the eccentric sleeve and having cylindrical bearing engage-v ment with the end of such piston and with said sleeve, and means serving to cross-connect said pistons comprising a tension spring mounted under suiiicient stress to hold the enumerated parts in thrust reaction throughout the cycle of the pump; and connecting means, one engaging each piston and its slipper on areas on opposite sides of the bearing engagement between the piston said bearing area .is

and the slipper whereby maintained undiminished.

2. The combination of a pump, comprising at least one pair of substantially opposed single acting pistons, an eccentric sleeve interposed between said pistons, slippers, one slipper interposed between each piston and the eccentric sleeve and having cylindrical bearing engagei ment with the end of such piston and with said sleeve, and means serving to cross-connect said pistons comprising a tension spring mounted under sulcient stress to hold the enumerated parts in thrust reaction throughout the cycle of the pump; and stirrups, one stirrup, embracing each slipper, housed in a groove formed in the sleeve-engaging face thereof and hingedly connected with the corresponding piston. c 3. The combination of a pump, comprising at least one pair of substantially opposed single acting pistons, an eccentric sleeve interposed between said pistons, slippers, one slipper Interposed between each piston and the eccentric sleeve and having cylindrical bearing engagement with the end of such piston and with said pistons comprising a tension spring mounted under sufllcient stress to hold the enumerated parts in thrust reaction throughout the cycle of A the pump; and elastic stlrrups, vone engaging each slipper, each stirrup havingl opposed inturned ends in hook engagement with the corresponding piston at opposite sides thereof.

' 4. The combination of a pump, comprising at least one pair of substantially opposed single acting pistons, an eccentric sleeve interposed between said pistons, slippers, one slipper interposed between each vpiston and the eccentric' 10 said stirrups being mounted under initial stress.

MATTHEW W. HUBER. 

